In order to study the electronic state of Fe atoms and interatomic exchange interac-tions in solid solutions of Bi₂CaNb_2-2xFe_2xO_9-δwith perovskite structure, methods ofmagnetic dilution, NEXAFS, XPS and EPR spectroscopy were used. Increased values ofthe magnetic moment of iron atoms in solid solutions compared to pure spin valuesfor Fe(III) are explained by the presence of clusters of Fe(III) atoms predominantly withantiferromagnetic type of exchange. Exchange parameters and cluster distribution inBi₂CaNb_2-2xFe_2xO_9-δsolid solutions depending on the Fe content were calculated accordingto the Heisenberg-Dirac-van Vleck model. The effect of calcium atoms on the clusterizationdegree and intensity of Fe interatomic exchange interactions was displayed. XPS spectraof Bi₂CaNb_2-2xFe_2xO_9-δ, were identified to enable estimation of the effective charge of theatoms composing it. The analysis of the NEXAFS Fe2p-spectra of iron oxides and the iron-containing solid solutions revealed that Fe atoms were mainly in an oxidation state of +3.EPR spectra of Fe containing solid solution powder show an intense asymmetric line in thelow-field part of the spectra at g = 4.27 with weakly manifested shoulder g 8-10 and a broadcomponent in the g 2 range with a high-field wing.